Mount Prospect, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

206
FXUS63 KLOT 150006
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
706 PM CDT Sat Mar 14 2026

.KEY MESSAGES...

- Waves of showers and thunderstorms may occur on Sunday. There
  is a Level 2 out of 5 threat for severe thunderstorms Sunday
  afternoon mainly east of Interstate 55. The primary threat is
  damaging winds.

- A period of accumulating snow accompanied by northwesterly
  winds gusting over 40 mph may occur Sunday night into early
  Monday, mainly northwest of Interstate 55.

- A period of cold temperatures is expected Monday and Tuesday,
  with overnight wind chills ranging from 5 to 15 below,
  especially Tuesday morning.

- The period of cold temperatures should be brief with warming
  temperatures by the end of next week.

&&

.DISCUSSION...
Issued at 304 PM CDT Sat Mar 14 2026

Through Monday:

Forecast concerns continue to focus on the significant storm
system taking shape across the front range of the CO Rockies this
evening.

Lee cyclogenesis is slatted to occur this evening over the
central High Plains in response to a rapidly amplifying upper-
level shortwave diving southeastward across the central United
States. Ensemble model guidance remains in excellent agreement in
tracking the surface cyclone eastward across the mid-Missouri
Valley late tonight, then along or just south of the
Illinois/Wisconsin state line Sunday afternoon. Thereafter,
strengthening upper level diffluence ahead of the approaching
negatively tilted mid- level trough will foster a rapid deepening
of the low (to near 980 mb) as it lifts northward across lower
Michigan Monday afternoon.

This storm system will produce several hazardous weather threats
across our area Sunday into Monday. These include:

- Thunderstorms on Sunday, some possibly strong in the afternoon
  and early evening.
- Strong gusty south winds on Sunday, strongest southeast of
  I-55, where a wind advisory is in effect.
- Turning much colder and very windy from the northwest Sunday
  evening into Monday.
- Rain mixing with a brief period of sleet and freezing rain
  before transitioning to snow from west to east across the area
  Sunday evening and night.


Storm and Severe Threat Sunday:

At least a couple of waves of showers and thunderstorms are
expected on Sunday. The first period favorable for mainly elevated
storms will be during the morning hours of Sunday. Steep mid-
level lapse rates could support the possibility for small hail
with these storms. However, poor effective storm layer shear <25
kt suggests that organized severe storms are not likely with this
initial morning round of storms.

Later in the day, particularly from mid to late afternoon into the
early evening hours, the main storm system will be shifting across
far northern IL. As it does, intensifying low-level winds (60+ kt
at 850 mb) will foster a strongly sheared kinematic environment
in advance of the eastward shifting cold front. In spite of this,
the likely presence of low clouds in the warm sector through the
day and only modest near surface moisture (dewpoints in the low
50s) is expected to stunt destabilization ahead of the approaching
front. Nevertheless, strong convergence and forced ascent along
the cold frontal boundary should still be able to support a forced
line of shallow convection as it sweeps eastward across the area
late in the day into the early evening. The primarily threat with
this activity will be strong damaging wind gusts in excess of 60
mph.

Strong Non-Thunderstorm Winds Sunday:

Outside of the thunderstorms on Sunday, conditions are expected to
become very windy through the day, particularly across southern
sections of the area, where a Wind Advisory is in effect.
Increasing southerly winds, driven by rapid pressure falls in
advance of the approaching surface low, are expected to result in
gusts of 45, to perhaps briefly as high as 55 mph in the afternoon
and early evening. The presence of lower cloud cover may limit the
overall magnitude of the gusts to some extent. Because of this, in
collaboration with neighboring offices, we have opted to convert
the High Wind Watch to a Wind Advisory for Sunday into early
Sunday evening. It is possible that this advisory need to be
expanded a bit farther north with later forecast updates.


Winter Weather Threat Sunday night into Monday:

Rain will transition over the snow from west to east Sunday
evening as a much colder airmass quickly spills in across the area
along the backside of the deepening surface low moving into Lower
Michigan. While a short hour or so period of mixed precipitation
looks plausible, the main concern will the shift to accumulating
snow in the presence of increasingly gusty northwesterly winds
Sunday night into Monday morning. There continues to be some
differences amongst guidance in terms as to how much additional
moisture will fall as snow in the deformation band of the cyclone
into Monday morning. However, given the expected track of the
system, forecast thinking continues to favor the heaviest snow
axis from northwestern IL into WI, with much lighter amounts with
east-southeastward extent across our area. This results in general
forecast snow amounts in the 2 to 5 inch range in my far
northwest (near the Rockford area), dropping to only an inch or
two across the Chicago area and points southeast.

Snowfall totals will not really be the main story with this wintry
weather event. Really, the combination of falling snow with
blowing snow on gusty northwest winds (45+ mph gusts) will be the
primary concern locally with this event. While the snow character
will start quite wet with a ratio near 10:1, which may initially
limit accumulations on the wet/road ground, rapidly falling
temperatures through the column will support a more fluffy (more
blowable) snow late Sunday night into Monday. With this in mind,
conditions should become more hazardous with time Sunday night,
with the potential for periods of near blizzard conditions at
times, particularly across the more open areas of
northern/northwestern IL. These poor conditions are expected to
continue into Monday morning before the snow gradually tapers off
from south to north through the day on Monday.

No changes have been made to going Winter Storm Watch across the
Rockford area, owing to the fact that potential warning level
impacts will not onset here until sometime later Sunday evening.
We do envision that this gets transitioned to either a warning or
an advisory as we get closer to the event. Winter Weather Advisory
conditions could also expand east-southeast of the current watch
area due to the combination of poor visibility in snow and blowing
snow through Monday morning.

KJB


Monday Night through Saturday:

The low pressure system providing Monday`s weather will
continue to move east allowing for drier conditions over the
region. 850 mb temperatures are expected to drop down around
-20C overnight into Tuesday morning. Even as winds generally
will be subsiding through the overnight, they are expected to
remain breezy enough to drop wind chill values down to between
-5 to -15F.

As a strong upper level ridge is expected to grow over the
desert south west, weak northwest flow is forecast to remain
over the western Great Lakes. There is still good agreement of
another upper level shortwave embedded in the flow to pass over
the area late Tuesday into Wednesday morning. This could provide
another quick shot of some snowflakes to the area. But as the
previously mentioned ridge expands through the week,
temperatures are expected to rise into the 50s and possibly low
60s by the end of the work week with drier conditions.

DK

&&

.AVIATION /00Z TAFS THROUGH 06Z MONDAY/...
Issued at 706 PM CDT Sat Mar 14 2026

A strong low pressure system tracking across northern Illinois
Sunday afternoon will bring periods of strong winds and precip,
including TS, Sunday and Sunday night.

Earlier SN associated with a mid-level warm front has exited
north of the terminals, with any lingering IFR/MVFR ceilings
also dissipating and moving north over the next hour or so. VFR
conditions are then expected through the remainder of the
evening and overnight. ESE winds of 10 to 15 knots will veer SE
while beginning to gust to 25 knots overnight as a low-level jet
settles over the area.

Winds will shift S/SSW while beginning to gust over 30 knots by
late Sunday morning, with an axis of SHRA and embedded TS
crossing the terminals mid morning into early afternoon in
association with an approaching low-level warm front.

S/SSW winds will continue to increase during the afternoon,
with frequent gusts around 35 knots and possibly to 40 knots.
Increasing low-level moisture will yield the development of MVFR
ceilings as well as isolated to scattered light SHRA through
much of the afternoon.

A strongly forced line of SHRA with possible TS will cross the
terminals roughly in the 22-00Z window. The line will likely
contain IFR visibility and bring a brief SW wind shift to 40
knots or higher. While lightning coverage may be low, the
convective nature of the line warrants inclusion of TS mention
in the TAF.

Behind the line and below a mid-level dry slot, low-end MVFR to
possibly IFR ceilings and DZ are expected for much of the
evening. SW winds will diminish slightly during this time before
a main cold front shifts winds NW and increases gusts to over
30 knots. DZ may begin to transition to SN at the very end of
the period, with the highest chances of any accumulating SN
occurring beyond the TAF period late Sunday night.

Kluber

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...Winter Storm Watch from Sunday evening through Monday evening
     for ILZ003-ILZ004-ILZ008-ILZ010.

     Wind Advisory from 10 AM to 9 PM CDT Sunday for ILZ023-ILZ032-
     ILZ033-ILZ039-ILZ108.

IN...Wind Advisory from 10 AM CDT /11 AM EDT/ to 9 PM CDT /10 PM
     EDT/ Sunday for INZ001-INZ002-INZ010-INZ011-INZ019.

LM...Gale Watch from Sunday morning through Sunday evening for the
     IL and IN nearshore waters.

&&

$$

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